Think of it this way (cores per processor)
Each CPU die exists in a 3D space, but it is mostly flat, so more like a 2D space with layers on it.
130nm sq = 16900 '2D space used for X transistors'
90nm sq = 8100 '2D space used for X transistors'
65nm sq = 4225 '2D space used for X transistors'
45nm sq = 2025
32nm sq = 1024
22/23nm sq = 506.25 (apx)
16nm sq = 256 (apx)
So moving to 65nm (from 90nm) allows for a +91.7% increase in transistor count.
Then moving from say 12 to 13 layer manufacturing (as layers could be thinner on the smaller process) would allow for an additional +8.33% increase in transistor count.
Bringing the total to +107.67% increase (from 90nm to 65nm, as values above percentage multiply, not just add) in transistor count within the same 3D space.
If they then decide to implement Z-RAM as L2 cache they can then have 4x the cache (2 MB / 4 MB vs 512 KB / 1024 KB) while only using 80% the comparitive space (same process) for L2 cache..... or 40% the 'real' space (90nm -> 65nm).
eg: Using Z-RAM as cache would only use 80% of the space and permit a 4x increase in quantity of L2 cache on AMD processors.
End result = Expect Quad-Core Processors in 2007 with heaps more L2 cache at roughly similar prices to when Dual-Core processors where released, on a 65nm manufacturing process as, although it is 'possible' on 90nm, the processors would be 'large', yeild would thus be low (physically large dies), and require too much power to cool even though the surface area : contact ratio was higher.
You can figure it out using early high-school mathamatics alone, and 'common' physics plain sense.
PS: Using the above numbers (on dize size shrinks down to 16nm) you can see processors with over 16x the transistor count of current processors, eg: 8-16 cores, 64 MB L2/L3 cache, maybe a few dedicated 'processor element cores' specially designed for certain things, such as 'one-way' cryptography in consumer CPUs, offloading network I/O, specialist 'game elements' with very large register counts for SIMD and MIMD data processing, ..... and more.
Sure, it is a few years away, but it'll happen.... IA-64 may even take off 'again' under a new name around the same time frame.... but that is only 'speculation' on my part and nothing more at this time.